USB hard drive not recognized



I have a 2.5" drive in a USB 2.0 enclosure that I can not get recognized on
the machine it worked on for about a week and then for now reason (except
probably a Windows Update that automatically ran!) is unrecognized by the

Yes, it's formatted at 80GB has plenty of power, tried every port on the PC
and it's immediately recognized by every other machine I've plugged it into!
Other devices automatically are recognized (Treo, MP3 player, etc). I've
uninstalled all the USB hubs and then went back and uninstalled everything
that said USB. Then rebooted and let it reinstall with no recognition! It
doesn't show up in DM or DiskMgmt. System has winXP Pro SP2 and all recent

This has got to be explainable and correctable as I've read at least a dozen
others on this board that have had similar problems.





you have done everything to check it except try it in a different machine.
It could be a problem with the drive or the caddy.


Read again..."it's immediately recognized by every other machine I've plugged
it into" is clearly written below. So anyone else got an idea of why this is




I realize the following will probably be of little comfort or help to you
but the experience we've had with a variety of USB 2.0 devices, particularly
jump (flash, pen, thumb, etc.) drives, but also including USBEHDs, parallels
yours. And we know that many other users' experiences also have run into
these puzzling occurrences, i.e., *apparently* non-defective USB 2.0 devices
installed in *apparently* working USB 2.0 ports in an *apparently*
properly-configured system that simply don't work or work erratically, or
work in one machine and not in another. It's been an aggravating problem for
many of us because there doesn't seem to be a common denominator to explain
all these anomalies.

We've just about concluded that either there must be some fundamental
incompatibility inherent in the USB 2.0 specification that is causing these
types of problems as it involves the design and manufacture of these USB
devices, and/or the system protocols and devices that are employed to work
with these devices. Or perhaps it's just a matter of poor quality control in
the manufacture of these devices (even extending to the same make & model)
in that sometimes they work; sometimes they don't. Or perhaps some basic
incompatibility problem existing between the XP OS and the USB 2.0
specification that results in these puzzling occurrences. Whatever it is,
these problems we've continually run into with (mainly) portable USB 2.0
devices are both aggravating & puzzling.

Having said all this...

Here are some general troubleshooting tips we've been circulating. I realize
that some may not be relevant to your situation and you've probably employed
most, if not all of them already, but let me throw them out anyway...

1. Access Disk Management and see if the device is listed. If so, and
there's no drive letter assigned, see if you can assign a drive letter to
the device.
2. Connect the USB device *directly* to a USB port on the computer, not via
a USB hub. Try different USB ports if your computer has more than one.
3. Do not use a USB extension cable.
4. Try alternate powering on/off methods. If the USB device contains its own
power supply, try booting up with its power on, then try powering on only
*after* the system has booted to a Desktop.
5. Try a different USB cable.
6. In the USB controllers section of Device Manager, uninstall all the USB
controllers listed and reboot.
7. If the device in question is a USB external HD, first check out the HD
with the manufacturer's diagnostic utility. If it checks out OK, and you can
remove the HD from its enclosure (without voiding any applicable warranty),
do so and install the HD as an internal HD.
8. Access the website of the manufacturer of the USB device to determine if
there's any firmware update or info re the problem you're experiencing.

I note your USBEHD is a 2.5" device. We've found these devices to be
particularly troublesome if they don't contain their own power supply. Does

And please let us know if you've come up with a solution.

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